#include <stdlib.h>
#include <string.h>

#include <x509.h>

X509 *X509_open_cert(const char *path)
{
	X509 *cert;
	FILE *fp;

	if (!(fp = fopen(path, "r")))
		return NULL;

	cert = PEM_read_X509(fp, NULL, NULL, NULL);
	fclose(fp);

	return cert;
}

char *X509_get_common_name(X509 *cert)
{
	X509_NAME *subj;
	X509_NAME_ENTRY *entry;
	ASN1_STRING *data;
	unsigned char *cn;
	int idx;

	if (!(subj = X509_get_subject_name(cert)))
		return NULL;

	if ((idx = X509_NAME_get_index_by_NID(subj, NID_commonName, -1)) < 0)
		return NULL;

	if (!(entry = X509_NAME_get_entry(subj, idx)))
		return NULL;

	if (!(data = X509_NAME_ENTRY_get_data(entry)))
		return NULL;

	if (ASN1_STRING_to_UTF8(&cn, data) == 0)
		return NULL;

	return (char *)cn;
}